import os
import requests
import mimetypes
from openai import OpenAI
from duckduckgo_search import DDGS
from PIL import Image
import pytesseract
import io
import openpyxl

class GaiaAgent:
    def __init__(self):
        self.client = OpenAI(api_key=os.getenv("OPENAI_API_KEY"))
        self.instructions = (
            "You are a top-tier research assistant for the GAIA benchmark. "
            "You analyze documents, reason step by step, and always provide a single, concise, and correct answer. "
            "If a file is provided, extract all relevant information. Use only information from the question and file. "
            "Always output only 'Final Answer: <answer>' as the last line, no explanation after."
        )
        self.api_url = "https://agents-course-unit4-scoring.hf.space"

    def fetch_file(self, task_id: str):
        try:
            url = f"{self.api_url}/files/{task_id}"
            resp = requests.get(url, timeout=15)
            resp.raise_for_status()
            content_type = resp.headers.get("Content-Type", "")
            return resp.content, content_type
        except Exception as e:
            return None, None

    def ocr_image(self, img_bytes):
        try:
            img = Image.open(io.BytesIO(img_bytes))
            return pytesseract.image_to_string(img)
        except Exception as e:
            return "[ERROR: Unable to OCR image]"

    def read_excel(self, file_bytes):
        try:
            wb = openpyxl.load_workbook(io.BytesIO(file_bytes), data_only=True)
            sheet = wb.active
            rows = list(sheet.iter_rows(values_only=True))
            text = "\n".join(["\t".join(str(cell) if cell is not None else "" for cell in row) for row in rows])
            return text
        except Exception as e:
            return "[ERROR: Unable to read Excel file]"

    def web_search(self, query, max_results=3):
        try:
            ddgs = DDGS()
            results = ddgs.text(query)
            summaries = []
            for i, r in enumerate(results):
                if i >= max_results: break
                summaries.append(f"{r['title']}: {r['body']}")
            return "\n".join(summaries)
        except Exception as e:
            return f"[ERROR: Web search failed: {e}]"

    def call_llm(self, prompt):
        response = self.client.chat.completions.create(
            model="gpt-4o",
            messages=[
                {"role": "system", "content": self.instructions},
                {"role": "user", "content": prompt}
            ],
            temperature=0.0,
            max_tokens=1024,
        )
        return response.choices[0].message.content.strip()

    def parse_final_answer(self, text):
        for line in reversed(text.splitlines()):
            if "Final Answer:" in line:
                return line.replace("Final Answer:", "").strip()
        # fallback
        return text.strip()

    def __call__(self, question: str, task_id: str = None) -> str:
        file_context = ""
        file_text = ""
        file_type = None

        # Step 1: Download and process file if provided
        if task_id:
            file_bytes, content_type = self.fetch_file(task_id)
            if not file_bytes or not content_type:
                file_context = "[ERROR: Could not download file]"
            elif "image" in content_type:
                file_text = self.ocr_image(file_bytes)
                file_context = f"Extracted text from image:\n{file_text}\n"
            elif "spreadsheet" in content_type or "excel" in content_type or task_id.endswith(".xlsx"):
                file_text = self.read_excel(file_bytes)
                file_context = f"Extracted text from Excel:\n{file_text}\n"
            elif "text" in content_type or "csv" in content_type or "json" in content_type:
                file_text = file_bytes.decode(errors="ignore")[:6000]
                file_context = f"File content:\n{file_text}\n"
            else:
                file_context = "[Unsupported or unknown file type]\n"

        # Step 2: Use web search for open-domain/factual questions
        # Basic heuristics: if the question is about a person, place, number, award, year, etc., try a search
        search_needed = False
        search_keywords = ["who", "what", "when", "where", "name", "number", "how many", "first", "last", "award", "recipient"]
        if any(kw in question.lower() for kw in search_keywords):
            search_results = self.web_search(question)
            if search_results and "ERROR" not in search_results:
                file_context += f"\nHere are relevant web search results:\n{search_results}\n"
                search_needed = True

        # Step 3: Build LLM prompt
        prompt = (
            f"{self.instructions}\n\n"
            f"{file_context}"
            f"Question: {question}\n"
            "Show your reasoning step by step, then provide the final answer as 'Final Answer: <answer>'."
        )
        llm_response = self.call_llm(prompt)
        answer = self.parse_final_answer(llm_response)

        # Step 4: Enforce strict output: only final answer, no extra lines
        return answer